There is a need to develop new reliable method for the analysis of chromium in biological fluids to assess chromium deficiency and the effect of chromium as adjuvant therapy for type 2 Diabetes. Chromium has been used as a low-cost dietary supplement for the treatment of diabetes and its complications. The frequency of actual chromium deficiency in the population is unknown in part because reliable measures for assessing chromium status in humans are limited. This R21 application seeks NIH support to develop a novel method in a two-year period to analyze chromium in biological fluids. The proposed novel method involves two steps. In the first step, the Advanced Oxidation Process (AOP) - a combination of hydrogen peroxide and ozone or ultraviolet (UV) radiation - is used to breakdown biological/organic species in biological fluids and to oxidize Iow-valent chromium to chromate. Chromate is then analyzed in the second step by a new membrane-based, chromate-selective electrode. This membrane containing a di-ammonium dicationic ligand preconcentrates chromate for its electrochemical analysis. The electrode is easily regenerated for subsequent analysis of chromium. The new method is expected to be easier and cheaper to operate for chromium analysis than the current techniques. The chemicals used in the novel method are environmentally benign, and do not generate harmful residuals or by-products. If chromium exists at different oxidation states, this novel method, converting chromium to chromate, gives the total chromium content in biological fluids. The research results can be applied immediately in the analysis of chromium in biological fluids, a goal articulated in the NIH program Chromium as Adjuvant Therapy for Type 2 Diabetes and Impaired Glucose Tolerance (PA-01-114). [unreadable] [unreadable]